Bottom Line:
She was successfully treated with aciclovir on both occasions and, in the latter, went on to deliver a healthy infant.This case is compared with 17 cases of HSV encephalitis in pregnancy in the literature identifying a predominance in the late 2nd and 3rd trimesters, perhaps in part due to immunological changes in pregnancy.The clinical presentation is also compared with non-pregnant patients with HSV encephalitis in the largest prospective UK and European studies.

Background: Herpes simplex virus (HSV) encephalitis is the most common sporadic cause of encephalitis with significant morbidity and mortality that is drastically reduced by early antiviral treatment.

Case presentation: We report a 37 year old woman, 33 weeks pregnant, who presented with seizures due to proven HSV-1 encephalitis, and who had had a previous episode of probable viral encephalitis aged 14 years. She was successfully treated with aciclovir on both occasions and, in the latter, went on to deliver a healthy infant. This case is compared with 17 cases of HSV encephalitis in pregnancy in the literature identifying a predominance in the late 2nd and 3rd trimesters, perhaps in part due to immunological changes in pregnancy. The clinical presentation is also compared with non-pregnant patients with HSV encephalitis in the largest prospective UK and European studies. We also present practical advice on management from recent national guidelines.

Conclusion: When pregnant women present with new seizures, headache, impaired consciousness or altered behaviour urgent investigation is required to identify common diagnoses, such as eclampsia, venous sinus thrombosis and metabolic disturbances. Nevertheless, viral encephalitis is a very treatable cause of this presentation with potentially serious complications if missed, and may be more common in latter stages of pregnancy. Encephalitis should not be discounted if the patient is afebrile, has a normal Glasgow coma score, or the cerebrospinal fluid white cell count is only slightly elevated, as these features are well recognised in viral encephalitis.

Mentions:
In pregnant women presenting with seizures, headache, or altered behaviour, in addition to viral encephalitis the differential diagnosis includes and number of other structural and metabolic causes which must be excluded. Hyperemesis gravidarum in early pregnancy results in excessive vomiting producing electrolyte imbalance, which, if severe, may provoke seizures [28]. Eclampsia refers to seizures or coma as severe complications of pre-eclapmsia; this is identified by hypertension and proteinuria. Pregnancy increases blood viscosity and the risk of thrombosis; therefore if seizures were preceded by headache, especially if with features of raised intracranial pressure, then an MR venogram should be performed. Further differential diagnosis includes acute hepatitis, malaria, ischaemic stroke, or acute intermittent porphyria [29]. The UK guideline for the management of suspected viral encephalitis recommend intravenous aciclovir as soon as possible if the CSF or MRI findings suggest viral encephalitis, or within 6 hours if these results are not available (Figures 1 and 2) [1,27]. There are no specific guidelines for management of viral encephalitis in pregnancy, but there is accumulating evidence that aciclovir is safe in pregnancy and is not associated with an increase in birth defects [30]. As mortality in HSV encephalitis is reduced from >70% to <20-30% with aciclovir, and delay in starting treatment is associated with a worse outcome, treatment should be started promptly in all patients with suspected HSV encephalitis [1,27,31]. In pregnant patients with seizures the lowest effective dose of anti-epileptic drugs is preferable, avoiding polytherapy and particularly potentially teratogenic drugs [32]. Nevertheless, the aim should be seizure freedom as there is a risk to the foetus during tonic-clonic seizures [32]. There is currently no evidence to support the use of anti-epileptic drugs as primary prophylaxis in viral encephalitis, and no evidence to direct secondary prophylaxis [33,34].Figure 1

Mentions:
In pregnant women presenting with seizures, headache, or altered behaviour, in addition to viral encephalitis the differential diagnosis includes and number of other structural and metabolic causes which must be excluded. Hyperemesis gravidarum in early pregnancy results in excessive vomiting producing electrolyte imbalance, which, if severe, may provoke seizures [28]. Eclampsia refers to seizures or coma as severe complications of pre-eclapmsia; this is identified by hypertension and proteinuria. Pregnancy increases blood viscosity and the risk of thrombosis; therefore if seizures were preceded by headache, especially if with features of raised intracranial pressure, then an MR venogram should be performed. Further differential diagnosis includes acute hepatitis, malaria, ischaemic stroke, or acute intermittent porphyria [29]. The UK guideline for the management of suspected viral encephalitis recommend intravenous aciclovir as soon as possible if the CSF or MRI findings suggest viral encephalitis, or within 6 hours if these results are not available (Figures 1 and 2) [1,27]. There are no specific guidelines for management of viral encephalitis in pregnancy, but there is accumulating evidence that aciclovir is safe in pregnancy and is not associated with an increase in birth defects [30]. As mortality in HSV encephalitis is reduced from >70% to <20-30% with aciclovir, and delay in starting treatment is associated with a worse outcome, treatment should be started promptly in all patients with suspected HSV encephalitis [1,27,31]. In pregnant patients with seizures the lowest effective dose of anti-epileptic drugs is preferable, avoiding polytherapy and particularly potentially teratogenic drugs [32]. Nevertheless, the aim should be seizure freedom as there is a risk to the foetus during tonic-clonic seizures [32]. There is currently no evidence to support the use of anti-epileptic drugs as primary prophylaxis in viral encephalitis, and no evidence to direct secondary prophylaxis [33,34].Figure 1

Bottom Line:
She was successfully treated with aciclovir on both occasions and, in the latter, went on to deliver a healthy infant.This case is compared with 17 cases of HSV encephalitis in pregnancy in the literature identifying a predominance in the late 2nd and 3rd trimesters, perhaps in part due to immunological changes in pregnancy.The clinical presentation is also compared with non-pregnant patients with HSV encephalitis in the largest prospective UK and European studies.

Background: Herpes simplex virus (HSV) encephalitis is the most common sporadic cause of encephalitis with significant morbidity and mortality that is drastically reduced by early antiviral treatment.

Case presentation: We report a 37 year old woman, 33 weeks pregnant, who presented with seizures due to proven HSV-1 encephalitis, and who had had a previous episode of probable viral encephalitis aged 14 years. She was successfully treated with aciclovir on both occasions and, in the latter, went on to deliver a healthy infant. This case is compared with 17 cases of HSV encephalitis in pregnancy in the literature identifying a predominance in the late 2nd and 3rd trimesters, perhaps in part due to immunological changes in pregnancy. The clinical presentation is also compared with non-pregnant patients with HSV encephalitis in the largest prospective UK and European studies. We also present practical advice on management from recent national guidelines.

Conclusion: When pregnant women present with new seizures, headache, impaired consciousness or altered behaviour urgent investigation is required to identify common diagnoses, such as eclampsia, venous sinus thrombosis and metabolic disturbances. Nevertheless, viral encephalitis is a very treatable cause of this presentation with potentially serious complications if missed, and may be more common in latter stages of pregnancy. Encephalitis should not be discounted if the patient is afebrile, has a normal Glasgow coma score, or the cerebrospinal fluid white cell count is only slightly elevated, as these features are well recognised in viral encephalitis.